Certain electronic integrated circuit chips, such as bank card integrated circuit chips, may contain confidential data which may be coveted by pirates. Such confidential data may be contained in circuits located on the front surface side of the integrated circuit chip. To obtain the data, a pirate may carry out an attack from the back side or the front side of the integrated circuit chip.
In a type of attack, called etch attack, the pirate etches a portion of the back side of the integrated circuit chip. From this etched portion, the pirate etches cavities having a width of a few micrometers, for example, by using an ion beam, which extend towards the front surface until the circuits have been reached. Electric contacts with circuit elements are then created in the cavities, and the pirate uses these contacts to analyze the integrated circuit chip in operation.
In another type of attack, the pirate scans the integrated circuit chip with laser pulses. The impact of the laser beam disturbs the integrated circuit chip operation. The observation of the consequences of such disturbances on the activity of the circuits enables the pirate to carry out the attack. To disturb the integrated circuit chip operation, the pirate may also apply positive or negative potentials by means of a probe in contact with the integrated circuit chip, or induce currents or voltages in elements of the circuits by means of a coil arranged close to the integrated circuit chip. This type of attack is called fault injection attack.
In another type of attack, the pirate uses the electromagnetic radiation emitted by the integrated circuit chip to obtain the confidential data. Indeed, the switching of the logic gates forming a circuit generates electromagnetic radiation. Now, in a circuit, not all logic gates switch at each clock cycle and, thus, the electromagnetic emissions will be proportional to the number of switching logic gates. Due to the use of certain mathematical analysis algorithms (Hamming distance, etc.), it is possible to find the integrated circuit chip ciphering key based on an analysis of the variations of the electromagnetic emissions of the circuit.
Known attack detectors all have one or a plurality of the following disadvantages. Some only enable to detect a limited number of attack types, often a single one. Some are visible for the pirate. The addition of certain detectors causes modifications in the manufacturing process.